Highly electroactive thiazolium [5,4-d]thiazol-2,5-dicarboxylic acid-silver electrochemiluminescent metal-organic frameworks: synthesis, properties and application in glutathione detection.

Thiazolo[5,4-d]thiazole-2,5-dicarboxylic acid (HThz), a thiazolothiazole (TTz) derivative with carboxylic acid groups, was synthesized as a ligand for the creation of five MOFs, each associated with distinct metal ions including Ag, Mn, Co, Zn, and Cu. The cathodic electrochemiluminescence (ECL) of HThz and the resulting MOFs was investigated. HThz was found to generate ECL signals, but this process was heavily reliant on potassium persulfate (KSO) as a co-reactant. However, the Ag-MOF, formed with HThz as the ligand, exhibited substantial ECL signals without the need for any co-reactant, which is different from other metal-containing MOFs. The smaller band gap, higher electron mobility and the unique electrocatalytic activity of Ag ions were confirmed to be the reasons for the excellent ECL performance of Ag-MOF. The interaction between thiol group of glutathione (GSH) and Ag-MOF suppressed the ECL signal of the Ag-MOF-KSO system. Based on this, a sensitive ECL method for GSH was developed and effectively utilized for GSH quantification in cell lysates.